1. Field of the Invention
The present invention relates to telephony call processing in general and distributed call processing in particular.
2. Description of the Related Art
Switching allows the telephony service provider the ability to connect subscribers to each other, thus eliminating the need for direct connections between users. In the simplest scenario all subscribers have access to a single switch. Originations are processed by the switch and terminated to the desired subscriber if available. Because no single switch can provide service to all subscribers, switches are geographically distributed and interconnected to form a network. A subscriber origination can be processed at the local switch and then forwarded to another switch on the network serving the terminating subscriber.
In the case of long distance networks and international calls, there can be further intermediate switches (known as tandem switches) if the originating and terminating switches do not have direct connectivity.
FIG. 1 illustrates a sample call architecture of a switching network. Switching network 100 includes a calling party 102 who intends to place a call to called party 110. Calling party 102 places a call over L1 116 which is a network access point. Switch S1 104 receives the dialed digits from calling subscriber 102 and connects the call over T1 112 intermachine trunk to switch S2 106, which in turn switches the call over T2 114 intermachine trunk to switch S3 108. Switch S3 108 then in turn connects the call to called party 110 over L2 118 link egress point.
Originating services are processed at the access point and terminating services at the egress point. Although every switch processes the call, there is no added value processing at the tandem switch. It is used to route the call further and provide a voice path throughout the network.
Within a switch, modern call processing generally uses call segments (or call halves) in a simple two way call to divide the work. Each agent is processed by its own call segment. Call segments simplify the implementation of complex services involving more than two agents by encapsulating the processing required for an agent including protocol and services. Call events are passed between connected call segments as necessary. Some architectures place the call segments on the switch itself, while others such as AIN (Advanced Intelligent Network) distribute the intelligence across hardware platforms. When call segments reside on separate platforms they must communicate with each other via a LAN (Local Area Network) or some other form of network communication. Intelligent Networking (IN) uses connection oriented TCAP/INAP messaging (Transaction Capabilities Application Part/Intelligent Network Access Point).
Referring now to FIG. 2, Network 200 illustrates another aspect of current call processing. Originating call processing segments 212, 216, and 220 correspond to switches 208, 224, and 228 respectively. As in FIG. 1 the switches are interconnected by intermachine trunks T1, T2 222, 226. Terminating call processing is performed in 210, 214, 218 which also correspond to switch S1, switch S2 and switch S3 208, 224, 228.
The call segments can either be distributed or local to the switch. Regardless of the implementation of the segments, they are associated with the switch and corresponding agent. At switch S1 208, O 212 performs processing for L1 204, and T 210 performs processing for T1 222. At switch S2 224, T1 222 becomes an origination and terminates to T2 226 by way of terminating call processor 214. At switch S3 228, T2 226 becomes an origination point which terminates off network by T2 218 to link egress point L2 230 before eventual connection to called party 232.
A drawback to the above identified network call segment processing scheme include requiring a single call to be processed at every switch it enters. Further, there is no added value in the tandem processing.
In FIG. 2 every call half associated with an intermachine trunk is merely forwarding the initial origination at the network access point. Additionally, originating service information needed at the network egress point must be encoded into the intermachine protocol. This adds unnecessary complexity to services.
There is accordingly a need for a new method and apparatus in order to solve or ameliorate one or more of the above described problems.